Mapping Potential Metro Rail Ridership in Los Angeles County 2013 Bin (Owen) Mo Los Angeles Metropolitan Transportation Authority (LACMTA) Abstract. Los Angeles County, is coping with increasing street and highway traffic. Public transit, and particularly rail, often is regarded as a strategy to help reduce urban traffic congestion, and growing awareness of global climate change. The objectives of this paper are to identify the poten- tial ridership and current utilization of the Metro Rail System of Los Ange- les County using the process of “Trip Generation,” to support visual plan- ning about public transit. The potential ridership produced and attracted to each station was estimated using Origin-Destination (O-D) flow patterns from residential and employment regions. Estimation of the number of po- tential riders accessing the Metro Rail System involves a spatial analysis of the location of current Metro Rail stations serving populations in a reasonable access time by walking. Service Area Zones (SAZ) then were delineated and mapped to indicate the areas that the potential riders could be served by existing stations within a ten minute walking interval. The po- tential ridership was measured to be approximately one million, a figure ten times larger than the present level of Metro Rail utilization. The analysis results across stations were compiled into the Atlas of Potential Metro Rail Ridership for the purpose of ridership promotion, system forecasting, and service planning. Keywords: Cartography, Transportation, GIS, Spatial Analysis and Mode- ling 1. Introduction Los Angeles County is internationally known as an automobile-oriented region. Like many metropolitan areas, Los Angeles County is struggling to control increasing street and highway congestion. Metro rail is an increa- singly attractive strategy to reduce traffic congestion in cities with high le- vels of automobile dependency. The Metro Rail System is the mass transit rail system in Los Angeles County and is run by the Los Angeles County Metropolitan Transportation Authority (LACMTA).It was estimated that 100,000 riders access the system by walking, based on the 2006 On-Board Survey records. As of this date, the system encompasses 87.8 route miles, serving six rail lines and 80 stations, with an average weekday boarding of 363,000 riders (LACMTA 2013) (Figure 1). The objectives of this paper are to identify the total potential ridership within walking access to the Metro Rail, and the current level of utilization therein, as well as the visual presentation of ridership access in the Atlas of Potential Metro Rail Ridership. To determine the potential ridership, a spatial analysis was completed to delineate Service Area Zones (SAZ) in which riders could access a station within a reasonable amount of time spent walking (ten minutes). Subsequently, the results were compiled into the Atlas for visual support of ridership promotion, system forecasting, and service planning. The article proceeds with four additional sections, which include a background, a description of the analysis method, an overview of the analysis and mapping results, and a conclusion. 2. Background Research has found that the spatial accessibility (i.e., travel distance and travel time) to a transit connection point is the primary determinant of transit use (Murray et al. 1998; Beimborn et al. 2003). Walking access is expected to have an important role in supporting service improvement planning by increasing accessibility and potential ridership levels. The con- cept of Origin-Destination (O-D) flow is fundamental to forecasting poten- tial ridership and its relationship to pedestrian access. Cartography is the generation of maps for the analysis, recognition, and prediction of spatial phenomena. The subsequent subsections treat the topics of walking access, O-D flow, and how spatial phenomena are represented cartographically in public transportation analysis. Figure 1. Map of 2013 Los Angeles County Metro Rail System 2.1. Walking Access The term "access" regarding public transportation refers to the ability to make use of the transit system. Access often is perceived in spatial terms based upon physical proximity to the service and associated cost in travel- ing to the service. As public transit is the most economical transportation option in Los Angeles County, the analysis focuses on travel distance and travel time as the main measure of accessibility, with a specific emphasis on walking. The choice of transportation mode for traveling to a transit station impacts the transportation management policy of an urban area. The primary form of accessing the Los Angeles Metro Rail system is by walking, with 52% of inbound riders traveling to the station by foot (Mo 2009). The percentage of walkers is higher for outbound riders of the Metro Rail system, as appro- ximately 80% of outbound riders walk from a station to their final destina- tions (LACMTA 2006). It is very important to know how much time Metro Rail riders are willing to walk, so that the effective service area of a transit station can be identified. According to AASHTO’s (American Association of State Highway and Transportation Officials) walking guideline, areas within approximately five minutes walking time (at three miles per hour) are considered “well- served.” Areas within approximately ten minutes’ walking time are consi- dered “served”. Beyond walking access, taking the bus, driving, and riding bicycles constitute other alternative access modes for people using metro rail. 2.2. Forecasting Origin and Destination Potential Ridership The Four-Step Travel Demand model is a well-known tool for forecasting future demand and performance of large-scale transportation systems (TCRB 2006; SCAG 2008; MWCG 2010). Trip Generation, the initial step in the Four-Step Travel Demand model, is applied to forecast potential ri- dership in Los Angeles County. Trip Generation predicts the number of daily rider trips originating from or destined for a given region (TCRB 2006; SCAG 2008; MWCG 2010). Origin and Destination (O-D) constitute the two “ends” for each trip, which are the portions on the journey between two activities. The potential ridership pro- duced from and attracted to each station is estimated using assumptions derived from residential and employment characteristics (Figure 2). Figure 2. Potential Ridership Generation of O-D Flow Origin ridership analysis focuses on residences. Residential population information is considered to be the most basic form of information about the travel patterns of a region. The number of potential riders is measured within the service area to calculate the possible number of trips using the transit service. Destination ridership analysis concentrates on employees. Employment regions are important local trip destinations. The actual or projected employment in an area determines the number of home-work trips that attract riders from the original areas (SCAG 2008; MWCG 2010). Destination ridership analysis also emphasizes trip attractors other than the workplace. Understanding the trip attractors in Los Angeles County beco- mes very important, particularly when estimating the Metro Rail potential ridership. The variety of trip attractors in Los Angeles County were identifi- ed through the regression coefficients for the trip attraction models employed in the year 2003 SCAG Regional Travel Demand Model. This model related the number of trip attractors to the number of employees working in different sectors of the employment region, including retail (for example, one employee leads to 4.678 trips), public administration (3.439), other services (3.303), art and entertainment and food (3.136), education and health (0.698), professional services (0.25), and information (0.227). The geographic locations of major residences and employment can be used to establish a need for a transit service based on the concept of O-D flow analysis. 2.3. The Use of Cartography in Public Transportation Analysis The cartographic method is to use various combinations of the procedures for analyzing and processing maps based on the rules of spatial arrange- ment of phenomena and their interrelationships, dependence, as well as development. A cartogram is a map in which the size of each entity is pro- portional to some value associated with the entity (Campbell 2001). Carto- grams not only came to define how transit maps were produced but also have potentially limited our ability to map transit systems even more effec- tively. Best known as a linear cartogram, the London Underground Tube map cre- ated in 1933 by Harry Beck has been widely adopted for other network maps around the world. For example, Beck’s map represents a subway sta- tion with a dot, which does not resemble the actual station at all but rather the relative position of a station along the route. Station connections are related to one another, and different fare zones, via color-coded lines connecting all of the related route stations via vertical, horizontal, 90- degree, and 45-degree angles. As a result, information is provided to the viewer without unnecessary visual clutter. The later application of this approach to the New York subway system map was, however, met with a different reaction. Not long after Mr. Massimo Vignelli’s version was released in August 1972, complaints arose (Heller 2010; Rawsthorn 2012) (Figure 4). Many New Yorkers were outraged for the geographic accuracy of the subway was done away with in order to show a clean interpretation of New York’s puzzling underground. The eye of the beholder was forced to see only the essentials. The public failed to recognize it as the map did not cater to their needs. Finally the M.T.A. bowed to the public by replacing the map, in 1979, with a geographical one. Making a meaningful map is the ultimate goal of cartographers. The desired goal is to allow map readers to extract and analyze information from the represented spatial data. This article searches alternative visualization me- thods of metro rail transit in Los Angeles County to see what enables us to extract and analyze information about current and potential ridership.